Analytical instruments are used in a number of applications to quantitatively and/or qualitatively analyze a sample of interest. Analytical instruments are often found in laboratories and are sometimes employed within processing operations. As used herein, an analytical instrument is any device, system or arrangement that is able to receive a sample of interest and provide an indication of some aspect of the sample of interest. Analytical instruments include, without limitation, process gas analyzers, NO/NOx analyzers, hydrocarbon analyzers, continuous emission monitoring systems and process gas chromatographs.
A variety of analytical instruments employ regulated flows and a variety of flow paths in order to provide analyses regarding various chemicals in processing or analytical contexts. The analytical instruments typically function using one or more flow devices that can initiate, interrupt, and reverse flow through the device. Such variety of flow functions is usually provided by a combination of one or more flow valves and/or pumps. In order to function effectively, analytical instruments will generally include a plurality of sample flow paths. In the context of a gas chromatograph, there are a number of flow paths used to introduce a flow of sample and carrier gas into the analytical instrument; flow a controlled amount of sample across a sorbent column; reverse the flow to elute the sample from the column; and detect the various components in the flow stream. Given the precise nature of such analytical instruments, it is very important that the flow paths themselves do not participate or otherwise affect the chemical make-up of the sample/carrier gas flow.
Typically, the variety of pneumatic or fluid connections of known process analytical instruments requires a variety of discrete tubing connections. While some advances have been provided to include compact planar manifold arrangements consisting of layered passages and gaskets or seals that replace the tubing, such efforts more closely resemble or emulate the planar manifolds of automotive transmission valve bodies and machine tool applications. For example, see U.S. Pat. No. 5,567,868 to Craig. Unfortunately, efforts to date have not resulted in a sufficiently low-cost or chemically-inert manifold.
As the art of process analytic devices has progressed, there is increasing pressure to provide a lower-cost higher-performance device.